Scientists Observe 'Negative Time' In Quantum Experiments (phys.org) 55
Researchers at the University of Toronto have experimentally observed "negative time" in photon interactions with atoms, suggesting a measurable effect rather than an illusion. The researchers stress that these findings, posted on the preprint server arXiv, don't imply time travel. Phys.Org reports: The experiments, conducted in a cluttered basement laboratory bristling with wires and aluminum-wrapped devices, took over two years to optimize. The lasers used had to be carefully calibrated to avoid distorting the results. [...] The explanation lies in quantum mechanics, where particles like photons behave in fuzzy, probabilistic ways rather than following strict rules.
Instead of adhering to a fixed timeline for absorption and re-emission, these interactions occur across a spectrum of possible durations -- some of which defy everyday intuition. Critically, the researchers say, this doesn't violate Einstein's theory of special relativity, which dictates that nothing can travel faster than light. These photons carried no information, sidestepping any cosmic speed limits. "We've made our choice about what we think is a fruitful way to describe the results," said Aephraim Steinberg, a University of Toronto professor specializing in experimental quantum physics, adding that while practical applications remain elusive, the findings open new avenues for exploring quantum phenomena.
"I'll be honest, I don't currently have a path from what we've been looking at toward applications," he admitted. "We're going to keep thinking about it, but I don't want to get people's hopes up."
Instead of adhering to a fixed timeline for absorption and re-emission, these interactions occur across a spectrum of possible durations -- some of which defy everyday intuition. Critically, the researchers say, this doesn't violate Einstein's theory of special relativity, which dictates that nothing can travel faster than light. These photons carried no information, sidestepping any cosmic speed limits. "We've made our choice about what we think is a fruitful way to describe the results," said Aephraim Steinberg, a University of Toronto professor specializing in experimental quantum physics, adding that while practical applications remain elusive, the findings open new avenues for exploring quantum phenomena.
"I'll be honest, I don't currently have a path from what we've been looking at toward applications," he admitted. "We're going to keep thinking about it, but I don't want to get people's hopes up."
Well duh. (Score:1, Funny)
I'll be honest, I don't currently have a path from what we've been looking at toward applications
Try porn, you dope.
Re: Well duh. (Score:2)
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Or micropsychiatry.
The Micropsychiatric Applications of Thiotimoline [wordpress.com]
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Re:Well duh. (Score:5, Insightful)
The question about "applications" is really stupid. Business majors need to learn to keep their damned single-track minds away from fundamental research.
This comment written before story posted in Negati (Score:2)
EoM
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Re: This comment written before story posted in Ne (Score:2)
Explain (Score:3)
These photons carried no information, sidestepping any cosmic speed limits.
How? Doesn't every particle carry some form of information? Are they saying these photons didn't have spin?
Re:Explain (Score:4, Interesting)
The wording is clumsy and "dumbed down", but blame the journalist for that.
I think what the physists are saying is there is no local hidden variable [wikipedia.org] that violate Bell's theorem [wikipedia.org].
They can't transmit FTL information in the same sense that entangled particles can't.
Are they saying these photons didn't have spin?
No.
Re:Explain (Score:5, Informative)
The wording is clumsy and "dumbed down", but blame the journalist for that.
I think what the physists are saying is there is no local hidden variable [wikipedia.org] that violate Bell's theorem [wikipedia.org].
They can't transmit FTL information in the same sense that entangled particles can't.
Which rally just means there is not actual claim of reversal of causality from a theoretical side. Which is good because otherwise they would have made an extraordinary claim that would require extraordinary evidence. Which leads to the question "if time is reversed, but you cannot use it for anything, is time really reversed?" or something like that. Anyways, things like this are interesting because they may actually invalidate Quantum Theory in very special circumstances. Or not. Remember that the "master" is not the theory but physical reality. The theory is just a tool and all known tools are flawed.
Re:Explain (Score:4, Informative)
Which leads to the question "if time is reversed, but you cannot use it for anything, is time really reversed?" or something like that.
Scientists aren't all that interested in the "really" part of that question. They're more interested in constructing a model that lets them make predictions. (The "why" question is met with similar insouciance.)
If imagining that time goes backwards helps to create such a model, then scientists might do it, without concern for whether that "really" happens.
There are plenty of constructions in theoretical physics that can't be "used" for anything, but can help with constructing theories. (Virtual photons come to mind.)
Remember that the "master" is not the theory but physical reality. The theory is just a tool and all known tools are flawed.
Okay, but some tools are less flawed than others, and some have yet to reveal their flaws (and may never.) We keep using the tools all the same, and keep an eye on them to make sure they haven't broken. But if or when they break, we don't lament -- instead, we celebrate the arrival of new science, and seek to repair or replace the tool with a better one.
Re:Explain (Score:5, Interesting)
A lot of physicists do mistake their models for reality, at least to hear them talk. They generally do not get into the philosophy behind the gap between their models and reality. In fact, most of them think philosophers do nothing important.
Recently, the most insightful import of their models and their relationship to reality has been coming from the philosophers, people like Tim Maudlin and David Albert are only the most visible, but there are many others. You can google for their interviews,
Maudlin's technical description of Bell's Inequality in a simple picture (with Carlo Rovelli):
https://www.youtube.com/watch?... [youtube.com]
Maudlin and Albert on the philosophical foundations of quantum mechanics:
https://www.youtube.com/watch?... [youtube.com]
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A lot of physicists do mistake their models for reality, at least to hear them talk.
Actually, I am a physicist. I don't do that, and have never met a colleague who does. That's not to say physicists and other scientists can't have a great deal of confidence in a model, to the point where it may seem like they think it corresponds to reality. But any scientist knows that their favorite theory is only one experiment away from being overthrown.
They generally do not get into the philosophy behind the gap between their models and reality. In fact, most of them think philosophers do nothing important.
Scientists are sometimes bemused by the efforts of philosophers. But I think they recognize that it's a different field with different objectives. I, f
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Whoever modded me down didn't take the time to read and understand what I wrote. I repeat: physicists, and scientists in general, do not "mistake" their models for reality. They consider the models to reflect reality insofar as they match observations. The models then become useful tools for predicting reality. When an observation contradicts a model, well, so much for the model: it needs to be fixed to reflect reality in this newly-observed realm.
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There are some fucked-in-the-head people here that get mod-points for some reasons. Hence here is a push, just in case.
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A lot of physicists do mistake their models for reality, at least to hear them talk.
Actually, I am a physicist. I don't do that, and have never met a colleague who does. That's not to say physicists and other scientists can't have a great deal of confidence in a model, to the point where it may seem like they think it corresponds to reality. But any scientist knows that their favorite theory is only one experiment away from being overthrown.
While I am not a Physicist, but I know a few, and I agree. Physicists usually know how this game works and the selection pressure for doing theoretical Physics is harsh enough that basically nobody stupid makes it. On the other hand, I am a PhD CS/IT type (with a lot of engineering skills) and I seem my own field regularly failing at this. It almost seems some CS/IT people are looking for God in their machines and frequently think they have found something like it. A significant part of the "AI" field falls
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While I am not a Physicist, but I know a few, and I agree. Physicists usually know how this game works and the selection pressure for doing theoretical Physics is harsh enough that basically nobody stupid makes it.
Agreed, but an observation: the truly brilliant physicists who break new ground are quite rare. The rest of us are reasonably competent, and make our contributions where we can.
To clarify: I was never in an avant garde area of theoretical physics. I worked in space science, and when the grant money ran out, eventually transitioned to work in industry as a data scientist with software engineering on the side. But I still call myself a physicist because that's where the bulk of my training is, and it's where
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> In fact, most of them think philosophers do nothing important.
Because mostly, they don't.
It's not like they don't want to. It's just that most philosophers have spent so much time in twirling words around that they didn't actually had any more time left to... you know... learn how stuff actually works, before they start going off about it.
They're like a super-duper-sleek wrench, ready to screw that bolt six ways from Sunday... but without anyone around to actually know how the car works, if that wrenc
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I disagree. The most important thing good (!) philosophers do is frame and ask questions and come up with though experiments. It is true that philosophy has almost no reliably verified research results, except that there is no absolute truth. And that result is subject to itself.
But asking questions and coming up with good ways to ask complex questions (as though experiments generally do) is a really important thing to do. Hence while we certainly do not need a lot of philosophy PhDs and professors, we cert
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Indeed. I just think it is important to repeat that occasionally, because many people do not know how that works and Science reporting in the media is often sensationalist crap.
Also agree that theory is mostly used to make predictions in Science. The reason is simple: Once you have a nice prediction, you can test it! If it works, great!, the theory just got a bit better verified. But if it fails, great!, you can make a new theory! The other reason to go indirectly via a theory is that it is exceptionally h
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Which leads to the question "if time is reversed, but you cannot use it for anything, is time really reversed?"
There are uses other than transmitting information.
Entangled particles can't be used to transmit information FTL, but they're still useful for encryption and authentication.
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My statement, quite obviously, was a joke.
Incidentally, entangled particles are completely worthless for encryption and authentication, and those are areas I happen to be an expert in. That story is just some crap lie used to sell "applications" that are not really there.
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Replying to your sig: "LLMs are machines that excel at predicting how to make stuff up to prompts, which sometimes turns out to be correct"
The NYT has an article on chemists and biologists using hallucination in LLMs trained on molecular folding (to put it quickly):
https://www.nytimes.com/2024/1... [nytimes.com]
In short, they want the hallucinations because it makes them investigate what-ifs and why-ifs. Apparently, they've had some success in creating new molecules with interesting properties from
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They are hallucinations. What happens here is that hallucinations are in some sense usually relatively close to truth, they are just one step removed in too many dimensions to be even an useful approximation of the truth. In the pure language case, details matter very much, put in or leave out a "not" and everything changes or ignore part of a sentence and you often get pure crap.
Chemistry is different. Cut part of a molecule or add something and there is a good chance you are still close to something that
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What if you send an entangled particle to a trader in another exchange and then you both measure your particles and make trades based on a protocol, like frontrunning faster than a regular light network can do it, but you can rightly plead ignorance because you did not know what stock you were going to frontrun until there was no time to tell your partner?
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That doesn't work, as theorized by John Stewart Bell and demonstrated by Alain Aspect.
Aspect experiment [wikipedia.org]
Aspect received the 2022 Nobel Prize in Physics for his experiment.
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Did you read my post, which uses the violation of Bell's inequality to get around frontrunning charges, since you don't know what the result of your measurement will be till you measure it, and your frontrunning partner is too far away to transmit a signal to before he measures his particle and makes his trade?
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Yes, I read it.
It's impossible to transmit information faster than light using entanglement.
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Yes, I read it.
It's impossible to transmit information faster than light using entanglement.
And yet, experiments show the opposite. When one entangled particle changes, the other changes instantly as well. No time delay. Distance, so far, does not seem to be an issue.
Re: Explain (Score:2)
Marbles can also do that.
I take a red marble and a blue marble, seal both in boxes, shuffle them, send a random box to you.
If I open my box and the marble is blue, your marble becomes red; if it's red, yours becomes blue--faster than the speed of light.
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How can regulators be sure you don't cheat and look at the marbles first, which would mean you are guilty of frontrunning?
With particles, can you keep your verifiable ignorance until the last moment when there is no time to send a light message, yet still know what to do to frontrun?
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And yet, experiments show the opposite.
No, they don't.
The Aspect Experiment showed the opposite of what you are claiming.
Alain Aspect has a Nobel Prize, and you don't, so I'll take his word over yours.
When one entangled particle changes, the other changes instantly as well. No time delay.
True. But there is no way to use that to transmit information.
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Can you use entanglement to frontrun financial trades is such a way that you can tell regulators you provably had no foreknowledge of what the other trader was going to do before they did it, and you made your trade faster than that other trader could transmit a message to you?
Re: Explain (Score:2)
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Quantum teleportation conveys information without any time delay
No, it doesn't. That is a common but fundamental misunderstanding of how entanglement works.
You better read up on that .
I already cited multiple authoritative references saying you're wrong.
You have cited nothing.
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https://brilliant.org/wiki/quantum-teleportation/
I found this which is just around my level to understand. Apparently, I didn't understand the mechanism/process, this explained it with slightly more detail than the article. It appears the process used is limited by the speed of light "Since step 3 involves communicating via some classical method, the information in the entangled state must respect causality"
Perhaps you could explain that further? Bob need
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How?
This is where physics gets weird. You don't even need to go as far as quantum mechanics to find this. Evanescent waves basically do this. They don't propagate, they are just "there", at the boundary of total internal reflection, with the same phase all the way along which essentially means there is no delay (infinite speed) between the start of the wave and any point along it.
But they don't carry information faster than light. As for particles, well, there's not a difference between a particle and colle
Randomization Slows Information (Score:2)
How? Doesn't every particle carry some form of information?
I suspect it is because the process is random i.e. the time the photons are emitted is not always before excitation. You see the same effect in tunneling photons that carry a signal. Those photoms travel faster than light in a vacuum but only a few of them make it across the tunneled gap and that means you have to wait for enough of them to cross to carry the signal and thus no information crosses the gap faster than light even though a the photons do. Technically these are also not really photons - they a
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No, they do not. (Score:2)
What they observe is that their _model_ needs a minus sign on the time parameter to continue to work.
That said, we still have no clue how quantum-effects and causality work together. The missing Quantum-Gravity is probably part of that, but as best as we know, causality requires consciousness and free will or it does not actually happen. Hence causality is coarse-grain, because whatever interface consciousness is using to influence physical reality is really slow compared with the typical "speed" of quantum
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Probabilistic? (Score:2)
If I read correctly the group delay is probabilistic with the member delay being distributed around the mean, with some delays more and some less. And they've measured the less to extend before the interaction.
This seems kinda normal in the quantum weirdness sense. Perhaps the negative time distance is bounded by some event horizon in the unruh sense.
The preprint and article could be written more clearly so maybe I'm misinterpreting.
Thanks for not explaining it. (Score:3)
I really did not want to know exactly what was set up, how they measured and optimized it, and finally what their explanation is for it (since you mentioned they have a plan for how they want to present this, but you didn't tell us what that is).
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All they are really announcing is hey everyone we need a negative value to make our math work, and happens to be the time value.
ban sqrt(-1) from math (Score:2)
This "negative time" stupidity most likely results as an artifact of idiots utilizing "i" in their equations .. yes that fucking i .. the so called hallucinatory number that is the cuckolding as the square root of negative one. It doesn't fucking exist. Stop using i in math!
No I'm not bitter about my C in college algebra.
Re: ban sqrt(-1) from math (Score:2)
I understand that you're joking, but mathematics loves beautiful abstract constructs like sqrt(-1). And there is nothing hallucinatory about it, unless you ask some stupid "AI" about it. The imaginary unit is very well defined in its own axiomatic model, and has proven itself time and again as an useful abstraction in both mathematics and physics, and possibly other areas.
It's not even that scary. I remember in my high school physics classes the teacher introduced it as a convenient means to describe the ef
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Re: ban sqrt(-1) from math (Score:2)
The photon is information. (Score:1)
Could it be that a photon that carries no information is, in fact, nothing at all.
Not SCIENCE (Score:1)
Science is a process. Hypothesis. Experiment. Results. Document. Repeatabilitity.
TIME is a thing we humans made up. It's that there is a monotonic increase of something which we call time. Think of it like "if here was no time we wouldn't have a ruler to see from WHEN things started to WHEN things ended.
There's no such thing as negative time or time travel no matter how suptid you are.
This is old news... (Score:2)